This paper focuses on the development of multibody numerical models to predict the dynamic response, aeroelastic stability, and blade loading of a soft-inplane tiltrotor wind-tunnel model. Comprehensive rotorcraft-based multibody analyses enable modeling of the rotor system to a high level of detail such that complex mechanics and nonlinear effects associated with control system geometry, and joint deadband may be considered. The influence of these and other nonlinear effects on the aeromechanical behavior of the tiltrotor model is examined. To assess the reliability of the multibody approach to rotorcraft analysis, the results obtained using two different rotorcraft-based multibody solvers are analyzed and compared. A parametric study of s...